1. Field of the Invention
This invention relates to a floating apparatus for an attractive magnetic floater, which is adapted to support a vehicle by magnetic attractive forces acting between a magnetic rail made of ferromagnetic material, such as iron, on a track and an electromagnet mounted on the vehicle and to guide the latter to its left or right whereby the vehicle may be supported and led in a non-contacting manner. More particularly, this invention relates to a magnetic floating apparatus for an attractive magnetic floater railway, which is adapted to support, guide, and propel the vehicle in a non-contacting manner by electromagnetic force and electromagnetic propulsion acting between an electromagnet, an armature of a linear inductor machine (hereinafter referred to as "LIM") on the vehicle, and a secondary conductor and a secondary iron core of the LIM.
2. Description of the Prior Art
FIG. 1 is a sectional view showing one construction of a magnetic floater of this class, wherein a chassis 1 is mounted by spring means 2 on a truck 3 which is provided with a linear induction motor armature 4 for propelling the vehicle, vehicle supporting electromagnets 5, and vehicle guiding electromagnets 6. A secondary iron core 8a and a secondary conductor 8b are mounted bilaterally of a track 9 to oppose the induction motor armature 4. Magnetic rails 7 for support and guidance are mounted bilaterally on the lower surface of an upper portion of the track 9. The supporting electromagnets 5 are opposite the undersides of the rails 7 and the guiding electromagnets 6 are located on either side thereof.
In a vehicle formed in this manner, the exciting current of the supporting and guiding electromagnets 5 and 6 is controlled to provide an attractive force acting between the magnetic rails 7 and the supporting and guiding electromagnets 5 and 6 to float the truck 3 over the track 9 and to guide the truck 3 to the left or right. This controls a current flowing in the linear induction motor armature 4 so that the vehicle is propelled over the track 9 by an electromagnetic force acting between the armature 4 and the secondary conductor 8b.
In a floating apparatus of this class, it is desired that the apparatus be compact and lightweight with low power consumption, sufficient electromagnetic force, and an electromagnetic spring constant. In addition the apparatus must easily follow the track and have low costs for construction and operation.
This requires that the magnetic rails be low in construction and maintenance costs and have low eddy current loss. A technique wherein the supporting and guiding electromagnets, as shown in FIG. 1, are arranged to place the N and S poles alternately in the direction of advancement to form a salient pole, minimizes leakage flux of the electromagnets and renders the latter lightweight to exhibit little inductance and excellent following of the track.
FIG. 2 shows one form of a floating apparatus according to the conventional technique wherein support and guiding magnetic rails 7a, 7b and sheet panel ferromagnetic materials are laminated in different directions to integrate and combine them for reducing eddy current loss and to form the magnetic rail 7 for support and guidance.
FIG. 3 shows another construction of a floating apparatus according to the conventional technique wherein the magnetic rail 7 is for support and guidance and the supporting and guiding rails 7a, 7b are bunched together while wire rods of ferromagnetic material are unified in an insulated condition so that eddy current loss occurring in the magnetic rail 7 is reduced against a magnetic field derived from the supporting magnets 5 and 6.
If the vehicle is run at a low speed, eddy current loss occurring in the magnetic rail 7 is so small that the magnetic rail is not required to be formed with a laminated structure and wire rods.
No consideration has been given, however, to flux distribution among the magnetic rails so that the sectional area of the magnetic rails 7 is simply the arithmetic addition of the supporting and guiding magnetic rails 7a, 7b and does not vary unless it is used with another element. This causes difficulty in reducing the cost of the magnetic rail.
If the magnetic rails 7 are formed with a laminated structure, two different structures of the magnetic rails must be used for floating and guiding the vehicle. The different directions of lamination give rise to defects and increase manufacturing cost. If the magnetic rails 7 are integrally formed of wire rods, a high degree of quality control is necessary because integration of the wire rods relies entirely on bonding. Also, insulation must be provided between the wire rods of ferromagnetic material to increase magnetic reluctance in a sectional direction. This causes an increase in power consumption for floatation because the exciting current of the electromagnet must be large.